Polymer and organic light-emitting diode including the same

ABSTRACT

A polymer having a repeating unit represented by Formula 1, wherein R 1  through R 14 , X 1 , and Ar 1  are the same as defined in the detailed description, and an organic light-emitting diode including the polymer are described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No.10-2011-0132128, filed on Dec. 9, 2011, and all the benefits accruingtherefrom under 35 U.S.C. § 119, the contents of which in their entiretyare herein incorporated by reference.

BACKGROUND

1. Field

The present disclosure relates to polymers and organic light-emittingdiodes including the polymers.

2. Description of the Related Art

Organic light-emitting devices are lightweight self-emissive devices,which are manufactured using a relatively small number of components bysimplified manufacturing processes. Organic light-emitting devicesprovide high-quality images and have wide viewing angles. Furthermore,organic light-emitting devices provide high color purity, realize fullmoving images, have low power consumption and operate at low voltage.Because of these characteristics, organic light-emitting devices aresuitable for use in any kinds of electronic devices.

Typically, an organic light-emitting device has a structure including asubstrate, an anode, organic layers, and a cathode, which aresequentially stacked on the substrate. The organic layers include a holetransport layer (HTL), an emission layer (EML), and an electrontransport layer (ETL).

When a voltage is applied to the anode and the cathode, holes injectedfrom the anode move to the EML via the HTL, and electrons injected fromthe cathode move to the EML via the ETL. The holes and electronsrecombine in the EML to generate excitons. The excitons radiativelydecay to emit light having a wavelength corresponding to the band gap ofa material.

Materials used to form organic layers may be classified as eithervacuum-depositable materials or solution-coatable materials according tothe method used to form the organic layer. Solution-coatable materialsshould be miscible with a solvent to form a composition that may becoated on a substrate by a known solution coating method, such as inkjetprinting, screen printing, or spin coating.

SUMMARY

An exemplary embodiment provides polymers having a novel structure.

Another exemplary embodiment provides organic light-emitting diodesincluding the polymers.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

Another exemplary embodiment provides a polymer which includes arepeating unit represented by Formula 1 below:

wherein X₁ is a single bond, —[C(R₂₀)(R₂₁)]_(a)—, —Si(R₂₂)(R₂₃)—, —S—,or —O—, and a is an integer of 1 to 5;

R₁ through R₁₄ and R₂₀ through R₂₃ are each independently hydrogen,deuterium, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, a phosphoric acid or a salt thereof, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₆₀ cycloalkyl group, asubstituted or unsubstituted C₃-C₆₀ cycloalkenyl group, a substituted orunsubstituted C₅-C₆₀ aryl group, a substituted or unsubstituted C₅-C₆₀aryloxy group, a substituted or unsubstituted C₅-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, —N(Q₁)(Q₂), or—Si(Q₃)(Q₄)(Q₅);

Q₁ through Q₅ are each independently hydrogen, deuterium, a halogenatom, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxyl group ora salt thereof, an ester group, a sulfonic acid group or a salt thereof,a phosphoric acid or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₃-C₆₀ cycloalkyl group, aC₅-C₆₀ aryl group, or a C₂-C₆₀ heteroaryl group; and

Ar₁ is a divalent group having two substituted or unsubstituted benzenerings that are linked to each other by a single bond or are fused witheach other via a 5-membered ring.

The polymer may further include an additional repeating unit representedby Formula 2 below:*

Ar₂

*′  Formula 2

wherein Ar₂ is a divalent group having two substituted or unsubstitutedbenzene rings that are linked to each other by a single bond, a divalentgroup having two substituted or unsubstituted naphthalene groups thatare linked to each other by a single bond, and a fluorenylene group.

According to another exemplary embodiment, an organic light-emittingdiode includes a substrate; a first electrode; a second electrode; andan organic layer interposed between the first electrode and the secondelectrode and including the polymer described above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of an exemplary embodiment ofan organic light-emitting diode (OLED);

FIG. 2 is a graph showing photoluminescence (“PL”) spectrum of a polymerP3 solution, according to an exemplary embodiment;

FIG. 3 is a graph showing voltage-current density characteristics ofOLEDs manufactured according to Example 1 and Comparative Example 1; and

FIG. 4 is a graph showing voltage-luminance characteristics of the OLEDsof Example 1 and Comparative Example 1.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer, or section discussed belowcould be termed a second element, component, region, layer, or sectionwithout departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. The term“or” means “and/or.” It will be further understood that the terms“comprises” and/or “comprising,” or “includes” and/or “including” whenused in this specification, specify the presence of stated features,regions, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toother elements as illustrated in the Figures. It will be understood thatrelative terms are intended to encompass different orientations of thedevice in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

“Aryloxy” as used herein means an aryl moiety that is linked via anoxygen (i.e., —O-aryl).

“Arylthio” as used herein means an aryl moiety that is linked via asulfur (i.e., —S-aryl).

“Salts” as used herein includes derivatives of the disclosed compoundsin which the parent compound is modified by making inorganic andorganic, base addition salts thereof, for example a Na, Ca, Mg, K,hydroxide, carbonate, bicarbonate, or the like salt.

“In a range” as used herein includes the endpoints of the recited range.

According to an embodiment, a polymer includes a repeating unitrepresented by Formula 1 below:

In Formula 1, X₁ may be a linking group that allows the twocarbazole-based condensed ring systems in Formula 1 to maintain a hightriplet potential. For example, X₁ may be a single bond,—[C(R₂₀)(R₂₁)]_(a), —Si(R₂₂)(R₂₃)—, —S—, or —O—. In this regard, a maybe an integer of 1 to 5.

R₁ through R₁₄ and R₂₀ through R₂₃ may each independently be hydrogen,deuterium, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, a phosphoric acid or a salt thereof, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₆₀ cycloalkyl group, asubstituted or unsubstituted C₃-C₆₀ cycloalkenyl group, a substituted orunsubstituted C₅-C₆₀ aryl group, a substituted or unsubstituted C₅-C₆₀aryloxy group, a substituted or unsubstituted C₅-C₆₀ arylthio group, asubstituted or unsubstituted C₂-C₆₀ heteroaryl group, —N(Q₁)(Q₂), or—Si(Q₃)(Q₄)(Q₅). In this regard, Q₁ through Q₅ may each independentlyhydrogen, deuterium, a halogen atom, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxyl group or a salt thereof, an ester group, asulfonic acid group or a salt thereof, a phosphoric acid or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₃-C₆₀ cycloalkyl group, a C₅-C₆₀ aryl group, or a C₂-C₆₀heteroaryl group.

For example, X₁ may be —[C(R₂₀)(R₂₁)]_(a)—. In this regard, R₂₀ and R₂₁may each independently be hydrogen, deuterium, a halogen atom, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxyl group or a saltthereof, an ester group, a sulfonic acid group or a salt thereof, aphosphoric acid or a salt thereof, a C₁-C₁₀ alkyl group, or a C₁-C₁₀alkoxy group. In one embodiment, R₂₀ and R₂₁ may each independently behydrogen. In this formula of X₁, a may be 1, 2, or 3. For example, a maybe 2.

In Formula 1, R₁ and R₂ may each independently be hydrogen; deuterium; ahalogen atom; a hydroxyl group; a cyano group; a nitro group; an aminogroup; an amidino group; a hydrazine group; a hydrazone group; acarboxyl group or a salt thereof; an ester group; a sulfonic acid groupor a salt thereof; a phosphoric acid or a salt thereof; a C₁-C₂₀ alkylgroup; a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxygroup that are substituted with a deuterium atom, a halogen atom, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxyl group or a saltthereof, an ester group, a sulfonic acid group or a salt thereof, and aphosphoric acid or a salt thereof; a phenyl group; a naphthyl group; ananthryl group; a phenanthrenyl group; a pyrenyl group; a chrysenylgroup; a pyridinyl group; a pyrimidinyl group; a pyrazinyl group; animidazolyl group; an indolyl group; or a phenyl group, a naphthyl group,an anthryl group, a phenanthrenyl group, a pyrenyl group, a chrysenylgroup, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, animidazolyl group, and an indolyl group that are substituted with adeuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, a phosphoric acid or a salt thereof, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group.

For example, R₁ and R₂ may each independently be hydrogen; a C₁-C₁₀alkyl group; a C₁-C₁₀ alkyl group that is substituted with a deuteriumatom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof; or Formulae3A through 3I, but are not limited thereto:

In Formulae 3A through 3I, Z₁ and Z₂ may each independently be hydrogen;deuterium; a halogen atom; a hydroxyl group; a cyano group; a nitrogroup; an amino group; an amidino group; a hydrazine group; a hydrazonegroup; a carboxyl group or a salt thereof; an ester group, a sulfonicacid group or a salt thereof; a phosphoric acid or a salt thereof; aC₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkyl group and aC₁-C₂₀ alkoxy group that are substituted with a deuterium atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof.

For example, Z₁ and Z₂ may each independently be a methyl group, anethyl group, a propyl group, an i-propyl group, a butyl group, ani-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptylgroup, an octyl group, a 2-ethylhexyl group, a nonyl group, a decylgroup, a 3,7-dimethyloctyl group, a methoxy group, an ethoxy group, apropyloxy group, an i-propyloxy group, a butoxy group, an i-butoxygroup, a t-butoxy group, a pentyloxy group, a hexyloxy group, aheptyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a nonyloxygroup, a decyloxy group, or a 3,7-dimethyloxy group, but are not limitedthereto.

In Formulae 3A through 3I, p may be an integer of 1 to 9, and q may bean integer of 1 to 4. If p is 2 or more, at least two Z₁ groups may beidentical to or different from each other. If q is 2 or more, at leasttwo Z₂ groups may be identical to or different from each other.

In Formula 1, R₁ and R₂ may be a protecting group for thecarbazole-based condensed rings to which R₁ and R₂ are linked. Thus, R₁and R₂ may be Formulae 3A through 3I, but are not limited thereto.

In Formula 1, R₃ through R₁₄ may each independently be hydrogen;deuterium; a halogen atom; a hydroxyl group; a cyano group; a nitrogroup; an amino group; an amidino group; a hydrazine group; a hydrazonegroup; a carboxyl group or a salt thereof; an ester group; a sulfonicacid group or a salt thereof; a phosphoric acid or a salt thereof; aC₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkyl group and aC₁-C₂₀ alkoxy group that are substituted with a deuterium atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof. For example,R₃ through R₁₄ may each independently be hydrogen, deuterium, a halogenatom, a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxyl group ora salt thereof, an ester group, a sulfonic acid group or a salt thereof,or a phosphoric acid or a salt thereof. For example, R₃ through R₁₄ mayeach independently be hydrogen, but are not limited thereto.

In Formula 1, the nitrogen atoms of the two carbazole-based condensedring systems are linked to each other via Ar₁. In addition, as shown byFormula 1′ below, the main backbone of the repeating unit of Formula 1can be traced from the 3^(rd) carbon atom of a first (the top)carbazole-based condensed ring system to the nitrogen atom of the firstcarbazole-based condensed ring system, to the Ar₁ group, to the nitrogenatom of a second (the bottom) carbazole-based condensed ring system, andto the 6^(th) carbon atom of the second carbazole-based condensed ringsystem.

Accordingly, it is possible to prepare a polymer in which energyproperties (e.g., high triplet potential, high HOMO energy level,excellent charge balancing properties) and charge conduction propertiesof the two carbazole-based condensed ring systems included in the mainbackbone of the repeating unit of Formula 1 are maintained at themaximum level. In particular, in the polymer including the repeatingunit of Formula 1, conjugation lengths may be maintained short and thusthe polymer may have a high triplet state energy level. In addition, therepeating unit of Formula 1 may increase a morphological stability of afilm comprising the polymer, and thus the characteristics of a deviceincluding the polymer comprising the repeating unit of Formula 1 may notdeteriorate during the operation and/or storage of the device. Forexample, deterioration of device characteristics that is caused bydefects due to aggregation of the polymer when a device including thepolymer operates may be substantially prevented.

The Ar₁ group may be a divalent group including two substituted orunsubstituted benzene rings. In this regard, the two substituted orunsubstituted benzene rings included in the Ar₁ group may be linked toeach other by a single bond or may be fused with each other via a5-membered ring. The backbone of the 5-membered ring may consist of onlycarbon atoms or may include hetero atoms such as O or S in addition tocarbon atoms.

For example, Ar₁ may be represented by one of Formulae 4A through 4Obelow:

In Formulae 4A through 4O, R₃₀ through R₃₂ may each independently be adeuterium atom; a halogen atom; a hydroxyl group; a cyano group; a nitrogroup; an amino group; an amidino group; a hydrazine group; a hydrazonegroup; a carboxyl group or a salt thereof; an ester group; a sulfonicacid group or a salt thereof; a phosphoric acid or a salt thereof; aC₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkyl group and aC₁-C₂₀ alkoxy group that are substituted with a deuterium atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof.

In Formulae 4A through 4O, R₄₀ through R₄₃ may each independently behydrogen; deuterium; a halogen atom; a hydroxyl group; a cyano group; anitro group; an amino group; an amidino group; a hydrazine group; ahydrazone group; a carboxyl group or a salt thereof; an ester group; asulfonic acid group or a salt thereof; a phosphoric acid or a saltthereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkylgroup and a C₁-C₂₀ alkoxy group that are substituted with a deuteriumatom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof.

In Formulae 4A through 4O, r and s may each independently be an integerof 1 to 5. For example, r and s may each independently be 1 or 2.

T₁ in Formulae 4N through 4O may be —O—, —S—, or —SO₂—.

In Formula 1, Ar₁ may be a divalent group including two substitutedbenzene rings. For example, Ar₁ may be represented by Formula 100 below(wherein, a detailed description of Q₁₀₀ is already provided in thedescription of R₃₀ above, t is an integer of 1 to 4), or Formula 4J or4K above. In this regard, a dihedral angle between the two substitutedbenzene rings, i.e., α of each of Formulae 100′, 4J′ and 4K′ may beabout 33° to about 82°:

In an exemplary embodiment, a polymer including the repeating unit ofFormula 1 wherein the dihedral angle α of Ar₁ is within the rangedescribed above may have a high triplet state energy level. The α valuemay be adjusted by varying the type and/or number of Q₁₀₀, R₄₀ and R₄₁groups in Formulae 100, 4J, and 4K.

In another exemplary embodiment, Ar₁ that satisfies the condition wherethe dihedral angle α is within the range described above may berepresented by one of Formulae 4B through 4K, but is not limitedthereto.

In yet another exemplary embodiment, the polymer may be a homopolymerconsisting essentially of the repeating unit of Formula 1 above.Alternatively, the polymer may be a homopolymer consisting of therepeating unit of Formula 1 above and terminal units derived fromFormula 1 above.

In still another exemplary embodiment, the polymer may be a copolymerfurther including an additional repeating unit represented by Formula 2below:*

Ar₂

*′  Formula 2

In Formula 2, Ar₂ is a divalent group including two substituted orunsubstituted benzene rings that are linked to each other by a singlebond, a divalent group including two substituted or unsubstitutednaphthalene groups that are linked to each other by a single bond, andfluorenylene. If Ar₂ is at least two different divalent groups, the Ar₂groups may be linked to each other by a single bond or via the repeatingunit of Formula 1. Ar₂ may be a divalent group having a symmetricalstructure.

For example, Ar₂ may be Formulae 5A through 5I, but is not limitedthereto:

In Formulae 5A through 5I, R₅₀ through R₅₅ may each independently behydrogen; deuterium; a halogen atom; a hydroxyl group; a cyano group; anitro group; an amino group; an amidino group; a hydrazine group; ahydrazone group; a carboxyl group or a salt thereof; an ester group; asulfonic acid group or a salt thereof; a phosphoric acid or a saltthereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkylgroup and a C₁-C₂₀ alkoxy group that are substituted with a deuteriumatom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof, and b may bean integer of 0 to 5 (e.g., an integer of 1 to 3).

Ar₂ may be represented by Formulae 5A-1 through 5A-4, 5B-1, 5B-2, 5C-1,5D-1, 5E-1, 5F-1, 5G-1, 5H-1, and 5I-1 below:

In Formulae 5A-1 through 5A-4, 5B-1, 5B-2, 5C-1, 5D-1, 5E-1, 5F-1, 5G-1,5H-1, and 5I-1, a detailed description of R₅₀ through R₅₂ is alreadyprovided above.

For example, in Formulae 5A-1 through 5A-4, 5B-1, 5B-2, 5C-1, 5D-1,5E-1, 5F-1, 5G-1, 5H-1, and 5I-1, R₅₀ through R₅₂ may each independentlybe a C₁-C₂₀ alkyl group (e.g., a C₁-C₁₀ alkyl group); a C₁-C₂₀ alkoxygroup (e.g, a C₁-C₁₀ alkoxy group); or a C₁-C₂₀ alkyl group and a C₁-C₂₀alkoxy group that are substituted with a deuterium atom, a halogen atom,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxyl group ora salt thereof, an ester group, a sulfonic acid group or a salt thereof,and a phosphoric acid or a salt thereof.

In yet another exemplary embodiment, the polymer may be a copolymerconsisting essentially of the repeating units of Formula 1 and Formula 2above. Alternatively, the polymer may be a copolymer consisting of therepeating units of Formula 1 and Formula 2 above and terminal unitsderived from Formula 1 and Formula 2 above. The copolymer may be random,block, or alternating as further described below.

The repeating unit of the polymer may be represented by Formula 1Abelow:

wherein a detailed description of R₁, R₂, and Ar₁ is already providedabove.

For example, in Formula 1A, R₁ and R₂ may each independently behydrogen; deuterium; a halogen atom; a hydroxyl group; a cyano group; anitro group; an amino group; an amidino group; a hydrazine group; ahydrazone group; a carboxyl group or a salt thereof; an ester group; asulfonic acid group or a salt thereof; a phosphoric acid or a saltthereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkylgroup and a C₁-C₂₀ alkoxy group that are substituted with a deuteriumatom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, anamino group, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof; a phenylgroup; a naphthyl group; an anthryl group; a phenanthrenyl group; apyrenyl group; a chrysenyl group; a pyridinyl group; a pyrimidinylgroup; a pyrazinyl group; an imidazolyl group; an indolyl group; or aphenyl group, a naphthyl group, an anthryl group, a phenanthrenyl group,a pyrenyl group, a chrysenyl group, a pyridinyl group, a pyrimidinylgroup, a pyrazinyl group, an imidazolyl group, and an indolyl group thatare substituted with a deuterium atom, a halogen atom, a hydroxyl group,a cyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxyl group or a salt thereof,an ester group, a sulfonic acid group or a salt thereof, a phosphoricacid or a salt thereof, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group(e.g., R₁ and R₂ may each independently be represented by one ofhydrogen; a C₁-C₁₀ alkyl group; a C₁-C₁₀ alkyl group that is substitutedwith a deuterium atom, a halogen atom, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxyl group or a salt thereof, an ester group, asulfonic acid group or a salt thereof, a phosphoric acid or a saltthereof; and Formulae 3A through 3I above), and Ar₁ may be representedby one of Formulae 4A through 4O (e.g., one of Formulae 4B through 4Kabove).

In addition, in Formula 1A, R₁ and R₂ may each independently berepresented by Formula 3A-1:

In Formula 3A-1, Z₁ may be a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group;or a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group that are substitutedwith a deuterium atom, a halogen atom, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxyl group or a salt thereof, an ester group, asulfonic acid group or a salt thereof, and a phosphoric acid or a saltthereof.

The polymer may include the repeating unit of Formula 1A described aboveand the additional repeating unit of Formula 2 wherein Ar₂ isrepresented by Formulae 5A through 5I (e.g., Formulae 5A-1 through 5A-4,5B-1, 5B-2, 5C-1, 5D-1, 5E-1, 5F-1, 5G-1, 5H-1, and 5I-1), but is notlimited thereto.

If the polymer further includes the additional repeating unit of Formula2, the polymer may be an alternating copolymer including of therepeating unit of Formula 1 and the additional repeating unit of Formula2, a block copolymer including blocks of the repeating unit of Formula 1and the additional repeating unit of Formula 2, or a random copolymerincluding the repeating unit of Formula 1 and the additional repeatingunit of Formula 2. If the polymer is a random copolymer including therepeating unit of Formula 1 and the additional repeating unit of Formula2, a molar ratio of the repeating unit of Formula 1 to the additionalrepeating unit of Formula 2 may be in the range of about 1:99 to about99:1, for example, in the range of about 3:7 to about 7:3. Even morespecifically, the molar ratio of the repeating unit of Formula 1 to theadditional repeating unit of Formula 2 may be about 5:5, but is notlimited thereto.

Examples of the C₁-C₂₀ alkyl group include, but are not limited to, amethyl group, an ethyl group, a propyl group, an i-propyl group, a butylgroup, an i-butyl group, a t-butyl group, a pentyl group, a hexyl group,a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, adecyl group, and a 3,7-dimethyloctyl group.

Examples of the C₁-C₂₀ alkoxy group include, but are not limited to, amethoxy group, an ethoxy group, a propyloxy group, an i-propyloxy group,a butoxy group, an i-butoxy group, a t-butoxy group, a pentyloxy group,a hexyloxy group, a heptyloxy group, an octyloxy group, a2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, and a3,7-dimethyloctyloxy group.

The substituent of the “substituted benzene” group and the “substitutednaphthalene” group is already described above in the description of R₃₀.

A weight average molecular weight (“Mw”) of the polymer including therepeating unit of Formula 1 may be in the range of about 1,000 Daltons(“Da”) to about 1,000,000 Da based on polystyrene, and a polymerdispersity index (“PDI”) thereof may be in the range of about 1.5 toabout 5; however, the weight average molecular weight and PDI of thepolymer are not limited thereto. For example, the polymer including therepeating unit of Formula 1 may be in the range of about 2,000 Daltons(“Da”) to about 500,000 Da based on polystyrene, and a polymerdispersity index (“PDI”) thereof may be in the range of about 1.5 toabout 3; or the polymer including the repeating unit of Formula 1 may bein the range of about 2,000 Daltons (“Da”) to about 10,000 Da based onpolystyrene, and a polymer dispersity index (“PDI”) thereof may be inthe range of about 1.5 to about 2. The weight average molecular weightand PDI (e.g. measured by gel permeation chromatography (“GPC”),calculated using polystyrene) may be adjusted by considering a structureand desired characteristics of an organic light-emitting diode includingthe polymer).

The term “substituted X” in “substituted or unsubstituted X (X is acertain substituent)” used herein refers to X in which at least onehydrogen atom of X is substituted with a deuterium atom; a halogen atom;a hydroxyl group; a cyano group; a nitro group; an amino group; anamidino group; a hydrazine group; a hydrazone group; a carboxyl group ora salt thereof; an ester group; a sulfonic acid group or a salt thereof;a phosphoric acid or a salt thereof; a C₁-C₆₀ alkyl group; a C₂-C₆₀alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group that are substituted with a deuterium atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof; a C₃-C₆₀cycloalkyl group; a C₃-C₆₀ cycloalkenyl group; a C₅-C₆₀ aryl group; aC₅-C₆₀ aryloxy group; a C₂-C₆₀ heteroaryl group; a C₃-C₆₀ cycloalkylgroup, a C₃-C₆₀ cycloalkenyl group, a C₅-C₆₀ aryl group, a C₅-C₆₀aryloxy group, and a C₂-C₆₀ heteroaryl group that are substituted with adeuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, a phosphoric acid or a salt thereof, aC₁-C₆₀ alkyl group, and a C₁-C₆₀ alkoxy group; —N(Q₁₀₁)(Q₁₀₂); or—Si(Q₁₀₃)(Q₁₀₄)(Q₁₀₅). In this regard, Q₁₀₁ through Q₁₀₅ may eachindependently be hydrogen, a halogen atom, a hydroxyl group, a cyanogroup, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substitutedor unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₆₀ cycloalkyl group, asubstituted or unsubstituted C₃-C₆₀ cycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, or a substituted or unsubstituted C₂-C₆₀ heteroarylgroup. If two or more substituents are present, the substituents may beidentical to or different from each other. The number of substituents islimited by the number of available valences of X.

For example, the term “substituted X” used herein refers to X in which ahydrogen atom of X is substituted with a deuterium atom; a halogen atom;a hydroxyl group; a cyano group; a nitro group; an amino group; anamidino group; a hydrazine group; a hydrazone group; a carboxyl group ora salt thereof; an ester group; a sulfonic acid group or a salt thereof;a phosphoric acid or a salt thereof; a C₁-C₂₀ alkyl group; a C₂-C₂₀alkenyl group; a C₂-C₂₀ alkynyl group; a C₁-C₂₀ alkoxy group; a C₁-C₂₀alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, and aC₁-C₂₀ alkoxy group that are substituted with a deuterium atom, ahalogen atom, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxyl group or a salt thereof, an ester group, a sulfonic acid groupor a salt thereof, and a phosphoric acid or a salt thereof; a C₃-C₂₀cycloalkyl group; a C₃-C₂₀ cycloalkenyl group; a C₅-C₂₀ aryl group; aC₅-C₂₀ aryloxy group; a C₂-C₂₀ heteroaryl group; a C₃-C₂₀ cycloalkylgroup, a C₃-C₂₀ cycloalkenyl group, a C₅-C₂₀ aryl group, a C₅-C₂₀aryloxy group, and a C₂-C₂₀ heteroaryl group that are substituted with adeuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, a phosphoric acid or a salt thereof, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; —N(Q₁₀₁)(Q₁₀₂); or—Si(Q₁₀₃)(Q₁₀₄)(Q₁₀₅). In this regard, Q₁₀₁ through Q₁₀₅ may eachindependently be hydrogen, a halogen atom, a hydroxyl group, a cyanogroup, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substitutedor unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₆₀ cycloalkyl group, asubstituted or unsubstituted C₃-C₆₀ cycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, or a substituted or unsubstituted C₂-C₆₀ heteroarylgroup. If two or more substituents are present, the substituents may beidentical to or different from each other. Again, the number ofsubstituents is limited by the number of available valences of X.

The unsubstituted C₁-C₆₀ alkyl group has a linear or branched structure.Examples of the unsubstituted C₁-C₆₀ alkyl group include methyl, ethyl,propyl, isobutyl, sec-butyl, pentyl, iso-amyl, hexyl, heptyl, octyl, andnonyl. A detailed description of the substituent of the substitutedC₁-C₆₀ alkyl group is already provided in the description of the“substituted X” above.

The unsubstituted C₂-C₆₀ alkenyl group denotes a terminal groupcontaining at least one carbon double bond in the middle or at the endof the unsubstituted C₂-C₆₀ alkyl group. Examples of the unsubstitutedC₂-C₆₀ alkenyl group may include ethenyl, prophenyl, butenyl, pentenyl,hexenyl, heptenyl, octenyl, propadienyl, isoprenyl, and allyl. Adetailed description of the substituent of the substituted C₂-C₆₀alkenyl group is already provided in the description of the “substitutedX” above.

The unsubstituted C₂-C₆₀ alkynyl group denotes a terminal groupcontaining at least one carbon triple bond in the middle or at the endof the unsubstituted C₂-C₆₀ alkyl group. For example, the unsubstitutedC₂-C₆₀ alkynyl group may be acetylenyl. A detailed description of thesubstituent of the substituted C₂-C₆₀ alkynyl group is already providedin the description of the “substituted X” above.

The unsubstituted C₁-C₆₀ alkoxy group has Formula of —OY (Y is theunsubstituted C₁-C₆₀ alkyl group) and may be, for example, methoxy,ethoxy, isopropyloxy, butoxy, or pentoxy. A detailed description of thesubstituent of the substituted C₁-C₆₀ alkoxy group is already providedin the description of the “substituted X” above.

The unsubstituted C₃-C₆₀ cycloalkyl group denotes a ring-type saturatedhydrocarbon group and may, for example, be cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, or cyclooctyl. A detailed description of thesubstituent of the substituted C₁-C₆₀ cycloalkyl group is alreadyprovided in the description of the “substituted X” above.

The unsubstituted C₃-C₆₀ cycloalkenyl group denotes a ring-typeunsaturated hydrocarbon group which has at least one carbon double bondand is not an aromatic ring. Examples of the unsubstituted C₃-C₆₀cycloalkenyl group include cyclopropenyl, cyclobutenyl, cyclopentenyl,cyclohexenyl, cycloheptenyl, a 1,3-cyclohexadienyl group, a1,4-cyclohexadienyl group, a 2,4-cycloheptadienyl group, and a1,5-cyclooctadienyl group. A detailed description of the substituent ofthe substituted C₃-C₆₀ cycloalkenyl group is already provided in thedescription of the “substituted X” above.

The unsubstituted C₅-C₆₀ aryl group denotes a monovalent group having aC₅-C₆₀ carbocyclic aromatic system, wherein the monovalent group may bea monocyclic or polycyclic group. In the polycyclic group, at least tworings included therein may be fused with each other. Examples of theunsubstituted C₅-C₆₀ aryl group include phenyl, pentalenyl, indenyl,naphthyl, azulenyl, heptalenyl, indacenyl, acenaphthyl, fluorenyl,spiro-fluorenyl, phenalenyl, phenanthryl, anthryl, fluoranthenyl,triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, picenyl, perylenyl,pentaphenyl, and hexacenyl. A detailed description of the substituent ofthe substituted C₅-C₆₀ aryl group is already provided in the descriptionof the “substituted X” above.

The unsubstituted C₂-C₆₀ heteroaryl group denotes a monocyclic orpolycyclic group including at least one ring and containing at least oneheteroatom ((e.g., N, O, P, Si, or S). In the polycyclic group, at leasttwo rings included therein may be fused with each other. Examples of theunsubstituted C₂-C₆₀ heteroaryl group include pyrrolyl, imidazolyl,pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, isoindolyl,indolyl, indazolyl, purinyl, quinolinyl, benzoquinolinyl, phthalazinyl,naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, carbazolyl,phenanthridinyl, acridinyl, phenanthrolinyl, phenazinyl, benzooxazolyl,benzoimidazolyl, furanyl, benzofuranyl, thiophenyl, benzothiophenyl,thiazolyl, isothiazolyl, benzothiazolyl, isoxazolyl, oxazolyl,triazolyl, tetrazolyl, oxadiazolyl, triazinyl, and benzooxazolyl. Adetailed description of the substituent of the substituted C₂-C₆₀heteroaryl group is already provided in the description of the“substituted X” above.

In the specification, “*” and “*′” denote a binding site with an atom ofan adjacent moiety, and may be easily understood by those of ordinaryskill in the art.

The polymer including the repeating unit of Formula 1 may be synthesizedusing a known organic synthesis method, such as Suzuki coupling orYamamoto coupling. The synthesis method of the polymer may be easilyunderstood by those of ordinary skill in the art with reference toExamples which will be described below.

The polymer includes the repeating unit of Formula 1 in which twocarbazole-based condensed rings systems have a high triplet potential,and thus the polymer may have a high triplet state energy level. Forexample, the polymer including the repeating unit of Formula 1 whereinAr₁ is a divalent linking group that satisfies the range of the dihedralangle α described above (e.g., Formulae 4B through 4K) may have a hightriplet level of the two carbazole-based condensed rings systems thatare linked to each other via Ar₁, thereby having a high triplet stateenergy level.

In addition, when the polymer further includes the additional repeatingunit of Formula 2, the polymer may have a high triplet state energylevel and a wide energy band gap even when a conjugation length of thepolymer is increased.

Moreover, the repeating unit of Formula 1 may have hole transportproperties and the additional repeating unit of Formula 2 may haveelectron transport properties. Thus the polymer may be a bipolar polymerin which both the hole transport moiety and the electron transportmoiety are present in the main backbone. Therefore, when the polymerdescribed above is used, the balance between the hole and electrontransport may be effectively obtained and maintained.

Accordingly, the polymer may be used as a material for forming anorganic layer of an OLED. For example, the polymer may be used as aphosphorescent host which is used in an emission layer of an OLEDtogether with a phosphorescent dopant.

As compared with a fluorescent material that has a maximum internalquantum efficiency of 25% since only singlet state energy contributes tolight emission, a phosphorescent material in which intersystem crossingbetween a singlet state energy level and a triplet state energy level ispossible has a theoretical internal quantum efficiency of 100% becauseexciton having triplet state energy also contributes to light emission.Therefore, an OLED including the phosphorescent material may have a highefficiency. Accordingly, considering the characteristics of the polymerdescribed above and the fact that a known phosphorescent dopantgenerally has a high triplet state energy level, the polymer may be usedas a phosphorescent host in an EML of an OLED.

For example, the polymer may be used as red, green, and/or bluephosphorescent host in an EML of an OLED. The polymer may be used as redand/or green phosphorescent host in an EML of an OLED, but is notlimited thereto.

According to another embodiment, an OLED includes a substrate; a firstelectrode; a second electrode; and an organic layer that is interposedbetween the first electrode and the second electrode and includes thepolymer comprising the repeating unit of Formula 1.

The organic layer may include an EML, and the EML may include thepolymer.

The EML may further include a phosphorescent dopant, and in particular aphosphorescent dopant for which the polymer may be a phosphorescenthost.

The phosphorescent dopant may be a known phosphorescent dopant. Forexample, the phosphorescent dopant may be an organometallic complexincluding iridium (Ir), platinum (Pt), osmium (Os), rhenium (Re),titanium (Ti), zirconium (Zr), and hafnium (Hf), but is not limitedthereto.

For example, the phosphorescent dopant may be bisthienylpyridineacetylacetonate iridium, bis(benzothienylpyridine) acetylacetonateiridium, bis(2-phenylbenzothiazole)acetylacetonate iridium,bis(1-phenylisoquinoline) iridium acetylacetonate,tris(1-phenylisoquinoline) iridium, tris(phenylpyridine) iridium,tris(2-biphenylpyridine) iridium, tris(3-biphenylpyridine) iridium,tris(4-biphenylpyridine) iridium, Ir(pq)₂(acac) (wherein “pq” is anabbreviation for 2-phenylquinoline, and “acac” is an abbreviation foracetylacetone, see Compound 10 below), Ir(ppy)₃ (wherein “ppy” is anabbreviation for phenylpyridine, see Compound 11 below),platinum(II)octaethylporphyrin (“PtOEP”, see a compound below), Compound12 below, Firpic (see Compound 13 below), Ir(piq)₃ (see a compoundbelow), Ir(piq)₂acac (wherein “piq” is an abbreviation forpenylisoquinoline, see Compound 14 below), Ir(mppy)₃ (see Compound 15below), Btp₂Ir(acac) (see a compound below), F₂Irpic (see a compoundbelow), (F₂ppy)₂Ir(tmd) (see a compound below), and Ir(dfppz)₃ (see acompound below), but is not limited thereto:

The organic layer interposed between the first electrode and the secondelectrode may further include a hole injection layer (“HIL”), a holetransport layer (“HTL”), a hole blocking layer (“HBL”), an electrontransport layer (“ETL”), and an electron injection layer (“EIL”), inaddition to the EML described above.

FIG. 1 is a schematic cross-sectional view of an OLED 10 according to anembodiment. Referring to FIG. 1, the OLED 10 includes a substrate 11, afirst electrode 12, a HTL 13, an EML 15, an ETL 16, an EIL 18, and asecond electrode 19. The OLED 10 and a method of manufacturing the samewill now be described in more detail.

First, a first electrode-forming material that has a high work functionis deposited, ion-plated, plated, or sputtered on the substrate 11 toform the first electrode 12. The first electrode 12 may constitute ananode that injects holes or a cathode that injects electrons. Thesubstrate 10, which may be any substrate that is used in general organiclight-emitting devices, may be a glass substrate or a transparentplastic substrate with excellent mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, and waterproofness.Examples of the first electrode-forming material include a metal oxide,a metal sulfide, and a metal, all of which have a high electricalconductivity. In general, these materials are used to form a thin film.Examples of the first electrode-forming material include indium oxide,zinc oxide, tin oxide, combinations thereof (e.g., indium tin oxide(“ITO”) and indium zinc oxide (“IZO”)), gold (Au), platinum (Pt), silver(Ag), and copper (Cu). In addition, polyaniline or a derivative thereof,or polythiophene or a derivative thereof may also be used as the firstelectrode-forming material. The first electrode 12 may have asingle-layered structure or a multilayered structure including at leasttwo layers. The first electrode 12 may include at least two differentmaterials. The thickness of the first electrode 12 may be appropriatelyadjusted by considering light transmittance and electrical conductivity,for example, in the range of about 10 nanometers (“nm”) to about 10micrometers (“μm”).

Next, although not illustrated in FIG. 1, if the first electrode 12 isan anode, a hole injection layer (“HIL”) may be further formed on thefirst electrode 12. The HIL may be formed by vacuum deposition, spincoating, casting, inkjet printing, or Langmuir-Blodgett (“LB”)deposition.

When the HIL is formed using vacuum deposition, the depositionconditions may vary with regard to the material that is used to form theHIL, and the structure and thermal properties of the HIL to be formed.In general, however, conditions for vacuum deposition may include adeposition temperature of about 100 to about 500 degrees Celsius (“°C.”), a vacuum pressure of about 10⁻⁸ to about 10⁻³ torr, and adeposition rate of about 0.01 to about 100 Ångstrom per second(“Å/sec”).

When the HIL is formed by spin coating, coating conditions may vary withregard to a compound that is used to form the HIL, and the desiredstructure and thermal properties of the HIL to be formed. In general,however, the coating speed may be in the range of about 2,000revolutions per minute (“rpm”) to about 5,000 rpm, and a temperature forheat treatment, which is performed to remove a solvent after coating,may be in the range of about 80 to about 300° C.

A material for forming the HIL may be a known hole injection material.Examples of the known hole injection material include phthalocyaninecompounds such as copper phthalocyanine, 4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA),N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), TDATA (see a formulabelow), and 2T-NATA (see a formula below), but are not limited thereto.

The thickness of the HIL may be in the range of about 100 to about10,000 Å, specifically, in the range of about 100 to about 1,000 Å. Whenthe thickness of the HIL is within this range, the HIL may haveexcellent hole injection properties without an increase in drivingvoltage.

Next, the HTL 13 may be formed on the first electrode 12 or the HIL byvacuum deposition, spin coating, casting, inkjet printing, or LBdeposition.

When the HTL 13 is formed by vacuum deposition or spin coating, thedeposition and coating conditions vary with regard to the compound used.In general, however, the condition may be almost the same as thecondition for forming the HIL.

A material for forming the HTL 13 may be a known hole transportingmaterial. Examples of the known hole transporting material include anamine derivative having an aromatic condensed ring, such asN,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine(“TPD”); polyaniline/dodecylbenzenesulfonic acid (“Pani/DBSA”, see aformula below);poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (“PEDOT/PSS”,see a formula below); polyaniline/camphor sulfonic acid (“Pani/CSA”);and polyaniline/poly(4-styrenesulfonate (“PANI/PSS”), but are notlimited thereto.

The thickness of the HTL 13 may be in the range of about 50 to about1,000 Å, specifically, in the range of about 100 to about 600 Å. Whenthe thickness of the HTL 13 is within the foregoing ranges, the HTL 13may have excellent hole transport properties without increase in drivingvoltage.

Next, the EML 15 may be formed on the HTL 13. The EML 15 may be formedby spin coating, casting, inkjet printing, or LB deposition. When theEML 15 is formed by spin coating, the coating condition may varyaccording to a used polymer and/or compound. In general, however, thecondition may be almost the same as the condition for forming the HIL.

The EML 15 may include the polymer including the repeating unit ofFormula 1 described above as a host. The EML 15 may further include aphosphorescent dopant. Examples of the phosphorescent dopant are alreadydescribed above.

If the EML 15 includes the polymer as a host and the phosphorescentdopant, the amount of the phosphorescent dopant in the EML 15 may be inthe range of about 1 weight percent (“wt %”) to about 10 wt % based on100 wt % of the EML 15. When the amount of the phosphorescent dopant iswithin this range, concentration quenching may be substantiallyprevented.

The EML 15 may include only the polymer including the repeating unit ofFormula 1 described above, or may further include a known fluorescentdopant, in addition to the polymer.

The thickness of the EML 15 may be in the range of about 100 to about1,000 Å, specifically, in the range of about 200 to about 900 Å. Whenthe thickness of the EML 15 is within this range, the EML 15 may haveexcellent light emission characteristics without an increase in drivingvoltage.

Although not illustrated in FIG. 1, a hole blocking layer may be furtherformed on the EML 15, if necessary.

The HBL may prevent triplet excitons or holes in the EML 15 fromdiffusing into the second electrode 19. The HBL may be formed by vacuumdeposition, spin coating, casting, or LB deposition. When the HBL isformed by vacuum deposition or spin coating, the deposition and coatingconditions vary according to a used compound. In general, however, theconditions may be almost the same as the condition for forming the HIL.Examples of a known hole blocking material include an oxadiazolederivative, a triazole derivative, a phenanthroline derivative, and TAZ(see a formula below), but are not limited thereto.

The thickness of the HBL may be in the range of about 50 to about 1,000Å, specifically, in the range of about 100 to about 300 Å. When thethickness of the HBL is within these ranges, the HBL may havesatisfactory hole blocking properties.

Next, the ETL 16 may be formed on the EML 15 or the HBL by vacuumdeposition, spin coating, or casting. When the ETL 16 is formed byvacuum deposition or spin coating, the deposition and coating conditionsvary with regard to the compound used. In general, however, theconditions may be almost the same as the conditions for forming the HIL.Examples of a material for forming the ETL 16 include any knownmaterials that stably transport electrons injected from an electroninjection electrode, i.e., a cathode, such as a quinoline derivative,4,7-diphenyl-1,10-phenanthroline (“Bphen”), BAIq (see a formula below),tris(8-quinolinorate)aluminum (“Alq₃”), berylliumbis(benzoquinolin-10-olate (“Bebq₂”), and TPBi (see a formula below).

The thickness of the ETL 16 may be in the range of about 100 to about1,000 Å, specifically, in the range of about 200 to about 500 Å. Whenthe thickness of the ETL 16 is within these ranges, the ETL 16 may havesatisfactory electron transport properties without an increase indriving voltage.

Next, the EIL 18 may be formed on the ETL 16 or the EML 15. The EIL 18may be formed from any known material, such as LiF, NaCl, CsF, Li₂O,BaO, or BaF₂.

The deposition conditions for the EIL 18 may vary according to a usedcompound. In general, however, the conditions may be almost the same asthe conditions for forming the HIL.

The thickness of the EIL 18 may be in the range of about 1 to about 100Å, specifically, in the range of about 5 to about 50 Å. When thethickness of the EIL 18 is within these ranges, the EIL 18 may havesatisfactory electron injection properties without an increase indriving voltage.

Lastly, the second electrode 19 may be formed on the EIL 19. The secondelectrode 19 may be formed using the same method as that used to formthe first electrode 12. The second electrode 19 may be a cathode or ananode. When the second electrode 19 is a cathode, the second electrode19 may be formed from a material having a low work function. Examples ofthe material forming the second electrode 19 include an alkali metal,such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), andcesium (Cs); an alkali earth metal, such as beryllium (Be), magnesium(Mg), calcium (Ca), strontium (Sr), and barium (Ba); a metal, such asaluminum (Al), scandium (Sc), vanadium (V), zinc (Zn), yttrium (Y),indium (In), cerium (Ce), samarium (Sm), europium (Eu), terbium (Tb),and ytterbium (Yb); alloys of at least two of these metals; alloys ofthese metals with gold (Au), silver (Ag), platinum (Pt), copper (Cu),manganese (Mg), titanium (Ti), cobalt (Co), nickel (Ni), tungsten (W),and tin (Sn); graphite; and graphite intercalation compound. Examples ofthe alloys include a Mg—Ag alloy, a Mg—In alloy, a Mg—Al alloy, an In—Agalloy, a Li—Al alloy, a Li—Mg alloy, a Li—In alloy, and a Ca—Al alloy.The second electrode 19 may have a single-layered structure or amultilayered structure including at least two layers. In addition, amaterial for forming the second electrode 19 may be used either alone orin combination with at least two other materials. The second electrode19 may be a transparent, semitransparent, or reflective electrode. Thethickness of the second electrode 19 may be in the range of about 10 nmto about 10 μm, but is not limited thereto.

One or more embodiments will now be described in more detail withreference to the following Examples. These Examples are for illustrativepurposes only and are not intended to limit the scope of the invention.

EXAMPLE Synthesis Example 1 Synthesis of Monomer 1

Monomer 1 was synthesized according to Reaction Scheme 1 below:

Synthesis of Intermediate 1.

A mixture of 20 g (112.7 mmol) of N-bromosuccinimide (“NBS”) and 50 mlof DMF was slowly added to a mixture of 20.0 g (102.4 mmol) ofiminodibenzyl and 50 ml of dimethylformamide (DMF), and the resultantmixture was stirred at room temperature (about 25° C.) to obtain 18 g ofIntermediate 1 (yield: 64%).

¹H-NMR (CDCl₃, 300 MHz): δ (ppm) 7.19-7.06 (m, 4H), 6.85-6.72 (m, 2H),6.63-6.61 (d, 1H), 5.99 (bs, 1H), 3.11-3.03 (t, 4H).

Synthesis of Intermediate 2.

A mixture of 3.44 g (19.3 mmol) of t-butylphenylboronic acid, 4.41 g(16.1 mmol) of Intermediate 1, 184 mg (0.8045 mmol) of palladium acetate(Pd(OAc)₂), 1.26 g (4.023 mmol) of tri(o-tolyl)phosphine ((P(o-tol)₃),16 ml of a 2.0 M K₂CO₃ aqueous solution, 135 ml of toluene, and 20 ml ofethanol (EtOH) was stirred at 100° C. to obtain 6.7 g of Intermediate 2(yield: 79%).

¹H-NMR (CDCl₃, 300 MHz): δ (ppm) 7.52-7.42 (m, 4H), 7.33-7.23 (m, 4H),6.84-6.74 (m, 3H), 6.07 (s, 1H), 3.18-3.12 (m, 4H), 1.55 (s, 9H).

Synthesis of Intermediate 3.

A mixture of 1.91 g (10.74 mmol) of NBS and 20 ml of DMF was slowlyadded to a mixture of 2.93 g (8.948 mmol) of Intermediate 2 and 20 ml ofDMF, and the resultant mixture was stirred at room temperature (about25° C.) to obtain 2.5 g of Intermediate 3 (yield: 70%).

¹H-NMR (CDCl₃, 300 MHz): δ (ppm) 7.52-7.43 (m, 4H), 7.36-7.18 (m, 4H),6.82-6.78 (d, 1H), 6.67-6.61 (d, 1H), 6.06 (s, 1H), 3.17-3.04 (m, 4H),1.38 (s, 9H).

Synthesis of Monomer 1.

A mixture of 696 mg (1.7155 mmol) of 4,4′-diiodo-1,1′-biphenyl, 1.39 g(3.431 mmol) of Intermediate 3, 31 mg (0.03431 mmol) oftris(dibenzylideneacetone)dipalladium(0)(Pd₂(dba)₃), 151 mg (0.06862mmol) of tri-tert-butyl phosphine (P(t-Bu)₃), 330 mg (3.431 mmol) ofNaOtBu, and 50 ml of toluene was stirred at 110° C. to obtain 1.3 g ofMonomer 1 (yield: 79%).

¹H-NMR (300 MHz, CDCl₃): δ (ppm) 7.56-6.80 (m, 28H), 3.06 (m, 8H), 1.39(s, 18H).

Synthesis Example 2 Synthesis of Polymer P1

Polymer P1 (alternating polymer) was synthesized according to ReactionScheme 2 below:

Synthesis of Polymer P1

A mixture of 500 mg (0.5193 mmol) of Monomer 1 synthesized according toSynthesis Example 1, 344 mg (0.5193 mmol) of Monomer 2, 5.8 mg (0.0260mmol) of Pd(OAc)₂, 40 mg (0.1298 mmol) of P(o-tol)₃, 4 ml (7.790 mmol)of K₂CO₃ (2.0 M in H₂O), Aliquat(R) 336 (200 μl, 2.0 M in toluene), and6 ml of toluene was stirred at 100° C. to obtain 750 mg of Polymer P1.

GPC: Mw=3.86×10³, Mn=2.12×10³, PDI=1.8

Synthesis Example 3 Synthesis of Polymer P2

Polymer P2 (alternating polymer) was synthesized according to ReactionScheme 3 below:

A mixture of 500 mg (0.5193 mmol) of Monomer 1 of Synthesis Example 1,400 mg (0.5193 mmol) of Monomer 4, 5.8 mg (0.0260 mmol) of Pd(OAc)₂, 40mg (0.1298 mmol) of P(o-tol)₃, 4 ml (7.790 mmol) of K₂CO₃ (2.0M in H₂O),Aliquat(R) 336 (200 μl, 2.0 M in toluene), and 6 ml of toluene wasstirred at 100° C. to obtain 804 mg of Polymer P2.

GPC: Mw=2.89×10³, Mn=1.91×10³, PDI=1.5

Synthesis Example 4 Synthesis of Polymer P3

Polymer P3 (random polymer) was synthesized according to Reaction Scheme4 below:

A mixture of 400 mg (0.4037 mmol) of Monomer 1, 229 mg (0.4029 mmol) ofMonomer 3, 554 mg (2.0145 mmol) of Ni(cod)₂ (cod=1,5-cyclooctadiene),315 mg (2.0145 mmol) of 2,2′-bipyridyl, and 10 ml of THF was stirred at60° C. to obtain 500 mg of Polymer P3.

GPC: Mw=7.34×10³, Mn=1.84×10³, PDI=3.9

Evaluation Example 1 Evaluation of Light-Emitting Properties of Polymers(in Solution)

Light-emitting properties of Polymer P3 were evaluated usingphotoluminescence spectrum of Polymer P3. First, Polymer P3 was dilutedin toluene to a concentration of 10 mM, and the PL spectrum of PolymerP3 was measured using an ISC PC1 Spectrofluorometer equipped with aXenon lamp. The results are illustrated in FIG. 2.

The results illustrated in FIG. 2 confirm that Polymer P3 in solutionexhibited excellent light-emitting properties.

Evaluation Example 2 Evaluation of Energy Gap and Triplet State Energyof Polymer

Highest occupied molecular orbital (HOMO) energy levels and tripletstate energy of Polymers P1, P2, and P3 were evaluated, and the resultsare shown in Table 1 below. The HOMO energy level was measured by cyclicvoltammetry. The cyclic voltammetry was performed using a PrincetonApplied Research EG&G potentiostat/galvanostat model 263 A equipped witha Pt wire as a pseudoreference electrode, a Pt wire as a counterelectrode, and Pt (diameter of 2 mm) as a working electrode.Acetonitrile was used as a solvent, and 0.1 M TBAPF₆ was used asupporting electrolyte in all experiments. A 0.1 M ferrocene/ferrocenium(F_(c)/F_(c) ⁺) couple served as an internal standard, and all reportedpotentials were referenced to its reversible potential. The ionizationpotential of each polymer is approximately equal to the onset oxidationpotential (vs. F_(c) ⁺/F_(c)) plus 4.8 eV (Fc+/Fc energy level below thevacuum level), which means that E(_(HOMO)) can be calculated using thefollowing equation: IP [eV]=E_(onset)+4.8 eV, which is the HOMO energylevel (E_(HOMO)) of polymer. Meanwhile, the triplet state energy wasmeasured such that a mixture of toluene and each Polymer (1 mg of eachpolymer was dissolved in 3 cc of toluene) were added to a quartz cell,liquid nitrogen (77° K) was added thereto, PL spectra of Polymers P1, P2and P3 were measured using a PL measuring device, and the PL spectrathereof were compared with general room-temperature PL spectra, therebyanalyzing peaks observed at only low temperatures.

TABLE 1 Triplet state energy (ET) HOMO energy level (eV) (eV, absolutevalue) Polymer P1 2.5 5.29 Polymer P2 2.5 5.27 Polymer P3 2.3 5.15

Example 1

A transparent electrode substrate formed by coating a glass substratewith 150 nm of indium-tin oxide was cleaned. Then, the ITO layer waspatterned into a desired pattern by using a photosensitive resin and anetchant, followed by cleaning. A hole transport layer-formingcomposition (Batron P 4083, available from Bayer AG) containing3,4-ethylenedioxythiopene (“PEDOT”) was spin coated on the ITO layer andthen baked at 200° C. for about 0.5 hours to form a HTL. An emissionlayer-forming composition (0.7 wt %) including chlorobenzene as asolvent, Polymer P3 as a host and Ir(mppy)₃ as a dopant (10 wt %) wasspin coated on the HTL and baked at 120° C. for 30 minutes to form anEML including Polymer P3 and Ir(mppy)₃. The hole transport layer-formingcomposition and the emission layer-forming composition were filteredusing a 0.2 mm filter before the spin coating processes. Theconcentrations and coating rates of the hole transport layer-formingcomposition and the emission layer-forming composition were adjusted toform a HTL having a thickness of 15 nm and an EML having a thickness of50 nm. TPBi was vacuum-deposited on the EML at a vacuum pressure of4×10⁻⁶ torr or less to form an ETL having a thickness of 40 nm. Then,LiF and Al were sequentially deposited on the ETL to form an EIL havinga thickness of 0.5 nm and a second electrode having a thickness of 100nm, thereby completing the manufacture of an OLED. The thickness andgrowth rate of each of the layers were adjusted using a crystal sensorduring the deposition process.

Comparative Example 1

An OLED was manufactured in the same manner as in Example 1, except thata mixture of PVK (number average molecular weight (“Mn”): from about25,000 to about 50,000/PDI: 2) and CBP (weight ratio of PVK to CBP is70:30) was used instead of Polymer P3 in the formation of the EML.

Structures of the OLEDs manufactured according to Example 1 andComparative Example 1 are shown in Table 2 below:

TABLE 2 EIL/ Anode HTL EML ETL cathode Example 1 ITO PEDOT:PSS PolymerP3:Ir (mppy)₃ TPBi LiF (0.5 nm) (150 nm) (15 nm) (10 wt %)¹ (50 nm) (40nm) /Al (100 nm) Comparative ITO PEDOT:PSS PVK:CBP¹:Ir (mppy)₃ TPBi LiF(0.5 nm) Example 1 (150 nm) (15 nm) (10 wt %)² (50 nm) (40 nm) /Al (100nm) ¹A weight ratio of PVK to CBP is 70:30. ²amount of Ir (mppy)₃ basedon 100 wt % of the EML

Evaluation Example 3 Characteristics Evaluation of OLED

Current density, current efficiency, and luminance of the OLED ofExample 1 were evaluated using a PR650 Spectroscan Source MeasurementUnit (available from PhotoResearch), and the results are illustrated inFIGS. 3 (graph showing voltage-current density characteristics) and 4(graph showing voltage-luminance characteristics).

Referring to FIGS. 3 and 4, it is confirmed that the OLED of Example 1including Polymer P3 has high current density, high current efficiency,and high luminance.

As described above, according to the one or more of the aboveembodiments, a polymer including a repeating unit of Formula 1 may havea high triplet state energy level and transport both holes andelectrons. Therefore, an OLED including the polymer may have highcurrent density and high luminance.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

What is claimed is:
 1. A polymer comprising a repeating unit representedby Formula 1 and an additional repeating unit represented by Formula 2:

wherein X₁ is —[C(R₂₀)(R₂₁)]_(a)—, —Si(R₂₂)(R₂₃)—, —S—, or —O—, and a isan integer of 1 to 5; R₃ through R₁₄ and R₂₀ through R₂₃ are eachindependently hydrogen, deuterium, a halogen atom, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxyl group or a salt thereof,an ester group, a sulfonic acid group or a salt thereof, a phosphoricacid or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₆₀cycloalkyl group, a substituted or unsubstituted C₃-C₆₀ cycloalkenylgroup, a substituted or unsubstituted C₅-C₆₀ aryl group, a substitutedor unsubstituted C₅-C₆₀ aryloxy group, a substituted or unsubstitutedC₅-C₆₀ arylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylgroup, —N(Q₁)(Q₂), or —Si(Q₃)(Q₄)(Q₅); Q₁ through Q₅ are eachindependently hydrogen, deuterium, a halogen atom, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxyl group or a salt thereof,an ester group, a sulfonic acid group or a salt thereof, a phosphoricacid or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₃-C₆₀ cycloalkyl group, a C₅-C₆₀ aryl group, ora C₂-C₆₀ heteroaryl group; Ar₁ is a divalent group having twosubstituted benzene rings that are linked to each other by a singlebond, and a dihedral angle between the two substituted benzene rings isin a range of about 33° to about 82°; and R₁ and R₂ are eachindependently represented by any one Formulae 3A through 3I:

wherein Z₁ and Z₂ are each independently deuterium; a halogen atom; ahydroxyl group; a cyano group; a nitro group; an amino group; an amidinogroup; a hydrazine group; a hydrazone group; a carboxyl group or a saltthereof; an ester group; a sulfonic acid group or a salt thereof; aphosphoric acid or a salt thereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxygroup; or a C₁-C₂₀ alkyl group and a C₂-C₂₀ alkoxy group that aresubstituted with a deuterium atom, a halogen atom, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxyl group or a salt thereof,an ester group, a sulfonic acid group or a salt thereof, and aphosphoric acid or a salt thereof; p is an integer of 1 to 9; and q isan integer of 1 to 4,*

Ar₂

*′  Formula 2 wherein Ar₂ is represented by any one of Formulae 5B-1,5B-2, 5C-1, and 5E-1:

wherein R₅₀ is a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀alkyl group and a C₁-C₂₀ alkoxy group that are substituted with adeuterium atom, a halogen atom, a hydroxyl group, a cyano group, a nitrogroup, an amino group, an amidino group, a hydrazine group, a hydrazonegroup, a carboxyl group or a salt thereof, an ester group, a sulfonicacid group or a salt thereof, and a phosphoric acid or a salt thereof.2. The polymer of claim 1, wherein X₁ is —[C(R₂₀)(R₂₁)]_(a)—, R₂₀ andR₂₁ are each independently hydrogen, deuterium, a halogen atom, ahydroxyl group, a cyano group, a nitro group, an amino group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxyl group or a saltthereof, an ester group, a sulfonic acid group or a salt thereof, aphosphoric acid or a salt thereof, a C₁-C₁₀ alkyl group, or a C₁-C₁₀alkoxy group, and a is 1, 2 or
 3. 3. The polymer of claim 1, wherein R₃and R₁₄ are each independently hydrogen; deuterium; a halogen atom; ahydroxyl group; a cyano group; a nitro group; an amino group; an amidinogroup; a hydrazine group; a hydrazone group; a carboxyl group or a saltthereof; an ester group; a sulfonic acid group or a salt thereof; aphosphoric acid or a salt thereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxygroup; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group that aresubstituted with a deuterium atom, a halogen atom, a hydroxyl group, acyano group, a nitro group an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxyl group or a salt thereof, an estergroup, a sulfonic acid group or a salt thereof, and a phosphoric acid ora salt thereof.
 4. The polymer of claim 1, wherein Ar₁ is represented byone of Formulae 4B through 4I:

wherein R₃₀ through R₃₂ are each independently a deuterium atom; ahalogen atom; a hydroxyl group; a cyano group; a nitro group; an aminogroup; an amidino group; a hydrazine group; a hydrazone group; acarboxyl group or a salt thereof; an ester group; a sulfonic acid groupor a salt thereof; a phosphoric acid or a salt thereof; a C₁-C₂₀ alkylgroup; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkyl group and a C₁-C₂₀alkoxy group that are substituted with a deuterium atom, a halogen atom,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxyl group ora salt thereof, an ester group, a sulfonic acid group or a salt thereof,and a phosphoric acid or a salt thereof; and R₄₀ through R₄₃ are eachindependently hydrogen; deuterium; a halogen atom; a hydroxyl group; acyano group; a nitro group; an amino group; an amidino group; ahydrazine group; a hydrazone group; a carboxyl group or a salt thereof;an ester group; a sulfonic acid group or a salt thereof; a phosphoricacid or a salt thereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; ora C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group that are substituted witha deuterium atom, a halogen atom, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxyl group or a salt thereof, an ester group, asulfonic acid group or a salt thereof, and a phosphoric acid or a saltthereof.
 5. The polymer of claim 1, wherein R₁ is same as R₂, R₃ is sameas R₁₃, R₄ is same as R₁₄, R₅ is same as R₉, R₆ is same as R₁₀, R₇ issame as R₁₁ and R₈ is same as R₁₂.
 6. The polymer of claim 1, whereinthe repeating unit is represented by Formula 1 is represented by Formula1A:

Ar₁ is represented by one of Formulae 4B through 4I:

wherein R₃₀ through R₃₂ are each independently a deuterium atom; ahalogen atom; a hydroxyl group; a cyano group; a nitro group; an aminogroup; an amidino group; a hydrazine group; a hydrazone group; acarboxyl group or a salt thereof; an ester group; a sulfonic acid groupor a salt thereof; a phosphoric acid or a salt thereof; a C₁-C₂₀ alkylgroup; a C₁-C₂₀ alkoxy group; or a C₁-C₂₀ alkyl group and a C₁-C₂₀alkoxy group that are substituted with a deuterium atom, a halogen atom,a hydroxyl group, a cyano group, a nitro group, an amino group, anamidino group, a hydrazine group, a hydrazone group, a carboxyl group ora salt thereof, an ester group, a sulfonic acid group or a salt thereof,and a phosphoric acid or a salt thereof; and R₄₀ through R₄₃ are eachindependently hydrogen; deuterium; a halogen atom; a hydroxyl group; acyano group; a nitro group; an amino group; an amidino group; ahydrazine group; a hydrazone group; a carboxyl group or a salt thereof;an ester group; a sulfonic acid group or a salt thereof; a phosphoricacid or a salt thereof; a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkoxy group; ora C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group that are substituted witha deuterium atom, a halogen atom, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxyl group or a salt thereof, an ester group, asulfonic acid group or a salt thereof, and a phosphoric acid or a saltthereof.
 7. The polymer of claim 1, wherein the polymer is analternating copolymer comprising the repeating unit of Formula 1 and theadditional repeating unit of Formula 2 or a random copolymer comprisingthe repeating unit of Formula 1 and the additional repeating unit ofFormula
 2. 8. The polymer of claim 1, wherein the polymer has a weightaverage molecular weight in a range of about 2,000 Da to about 1,000,000Da.
 9. An organic light-emitting diode comprising a substrate; a firstelectrode; a second electrode; and an organic layer interposed betweenthe first electrode and the second electrode and comprising the polymerof claim
 1. 10. The organic light-emitting diode of claim 9, wherein theorganic layer comprises an emission layer, wherein the emission layercomprises the polymer.
 11. The organic light-emitting diode of claim 10,wherein the emission layer further comprises a phosphorescent dopant forwhich the polymer is a phosphorescent host.
 12. The organiclight-emitting diode of claim 11, wherein the phosphorescent dopantcomprises an organometallic complex comprising one of iridium (Ir),platinum (Pt), osmium (Os), rhenium (Re), titanium (Ti), zirconium (Zr),hafnium (Hf), and any combinations thereof.
 13. The organiclight-emitting diode of claim 11, wherein an amount of thephosphorescent dopant in the emission layer is in a range of about 1 wt% to about 10 wt %.
 14. The polymer of claim 1, wherein X₁ is—Si(R₂₂)(R₂₃)—, —S—, or —O—.